Experiments will be undertaken with the aim of clarifying the role of the intracellular pool of free alpha-chains in modifying the rate of synthesis of Beta-chains, and to determine if this process functions as a regulatory mechanism for coordinated synthesis of the complementary globin chains of hemoglobin. These studies will be carried out with intact reticulocytes obtained from individuals with alpha- thalassemia and from non-thalassemic individuals with hemolytic anemia. The studies will involve determination of alpha and Beta globin synthesis by the intact reticulocytes in vitro.